1. Field of the Invention
The present invention relates to a defect inspection apparatus, a program, and a manufacturing method of a semiconductor device.
2. Related Background Art
A method has been proposed in which a rectangular electron beam is applied to a sample, a secondary electron, a reflective electron, and a back-scattered electron generated in accordance with a variation of a shape/material/potential of a sample surface are enlarged/projected to acquire a sample surface image, and the image is applied to defect inspection of a semiconductor pattern (e.g., Japanese Patent Laid-Open (kokai) Nos. 07-249393 and 11-132975).
A schematic procedure of a general defect inspection method using a mapping projection type electron beam defect inspection apparatus according to a conventional technique is described. First, after setting parameters such as inspection sensitivity and electron beam condition, inspection is executed, a place extracted as a defect is reviewed in order to confirm an inspection result or optimize sensitivity. At a reviewing time, a magnification is preferably set to be higher than that at an inspection time, and imaging is performed in order to judge whether a defect is true or false. Therefore, inspection sensitivity is checked. When the sensitivity is satisfactory, the inspection is ended. However, when the sensitivity is insufficient, a parameter value is set again, and the above-described procedure is repeated until sufficient sensitivity is obtained.
However, since the mapping projection type electron beam defect inspection apparatus is originally designed in such a manner as to be optimum for the magnification at an inspection time, the apparatus is not suitable for imaging with a high magnification and resolution. Therefore, for example, to cover both the magnifications at an inspection time and at a reviewing time by a single beam lens column, there is a problem that the apparatus becomes huge. Additionally, there is also a method of separately installing a beam lens column for reviewing, but the method is not so preferable.
Additionally, for example, a control electrode is disposed right above a wafer which is a sample, or a stage for supporting the wafer is set to be movable in a Z-direction, and accordingly a working distance between the wafer and an objective lens is narrowed. Consequently, it is also possible to enhance an observation magnification without setting the apparatus to be huge.
However, a sufficient resolution or S/N cannot be obtained in this method.